21693688 has 16 divisors (see below), whose sum is σ = 40725360. Its totient is φ = 10833600.

The previous prime is 21693673. The next prime is 21693697. The reversal of 21693688 is 88639612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10933 + ... + 12763.

It is an arithmetic number, because the mean of its divisors is an integer number (2545335).

Almost surely, 2^21693688 is an apocalyptic number.

It is an amenable number.

21693688 is a deficient number, since it is larger than the sum of its proper divisors (19031672).

21693688 is a wasteful number, since it uses less digits than its factorization.

21693688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3318 (or 3314 counting only the distinct ones).

The product of its digits is 124416, while the sum is 43.

The square root of 21693688 is about 4657.6483336551. The cubic root of 21693688 is about 278.8973985000.

The spelling of 21693688 in words is "twenty-one million, six hundred ninety-three thousand, six hundred eighty-eight".